Syntheses of oxygen-containing derivatives from 3-carene
3-Carene, mainly existing in some special pine trees, such as Pinus longifolia and Pinus sylvestris Linn, is one of the few chiral source compounds with ternary ring structure. It is ranked α-pinene and β-pinene after as the third largest production monoterpene from turpentine. Traditional turpentines produced in China were low in 3-carene, so it did not have adequate resources for further researches. As a result, its research results were very few. However, a special Pinus szemaoensis species has been found in yunnan in recent years, the content of 3-carene in turpentine from which was up to 38%. With these pine trees reached resin tapping period in succession, the resource of 3-carene was more and more abundant, and researches on it has received increasing attention.
The chemical name of 3-carene is 3,7,7- trimethylbicyclo [4.1.0] hept -3-ene,and there are a six-membered ring, a three-membered ring and a double bond in its molecular structure, so 3-carene is a compound with high reactivity. 3-carene could take various different kinds of reactions, including oxidation, addition, isomerization and dehydrogenation and so on, among which oxidation is one of the most effective ways for its modification.
In this paper, epoxidation of 3-carene was studied by using self-made phosphomolybdate tungsten heteropoly acid as catalyst and H2O2 as oxidant. The effects of solvent type, material ratio, reaction temperature and time on the reaction were investigated. The optimal preparation process of 3,4-epoxycarane was obtained as follows: trichloromethane as the solvent, the amount of catalyst was 2% of the mass of 3-carene, the amount of H2O2 was 1.2 times of the molar mass of 3-carene, reaction temperature was 35 oC and reaction time was 6 hours, the corresponding results of which were obtained as that conversion ratio of raw materials was 92.96% and the selectivity of product was 92.05%. Solvent type showed significant impact on the product composition. In most organic solvent systems except trichloromethane, 3,4-epoxycarane produced by epoxidation took place further ring-opening reaction and produced 3,4-carenediol.
In addition, allylic oxidation of 3-carene was made with CrO3-Al2O3 as catalyst and oxygen as oxidant. The effects of catalyst amount, temperature, time and oxygen flux on the oxidation were investigated. The optimum oxidation process was established as that catalyst amount was 3% of the mass of 3-carene, temperature was 25℃, time was 10 h and oxygen flux was 25 mL/min. Under the optimum process, the raw material conversion was 58.72%, and the total selectivity of α,β-unsaturated ketones was 86.07% (car-3-ene-2-one 19.83%, car-2-ene-4-one 4.61% and car-3-ene-5-one 61.63%).
Keywords: 3-carene, epoxidation, allylic oxidation, 3,4-epoxycarane, 3-carene-5-one
第一章 前言 7
1.1 研究背景及意义 7
1.2.2 合成蒈酮 9
1.2.3 合成蒈醇 9
第二章 3-蒈烯环氧化实验 11
2.1.2 设备 11
2.1.4 环氧化反应 11
2.1.5 产物分析 12
2.2.4 其他氧化工艺优化 14
第三章 3-蒈烯烯丙位氧化实验 17
3.1.5 产物分析 18